Gas turbine engines are often used to power aircraft and industrial power. A gas turbine engine may include, for example, five major sections, a fan section, a compressor section, a combustor section, a turbine section, and an exhaust section. The fan section is positioned at the front, or “inlet” section of the engine, and includes a fan that induces air from the surrounding environment into the engine, and accelerates a fraction of this air toward the compressor section.
The compressor section raises the pressure of the air it receives from the fan section to a relatively high level. Low and high pressure compressor components such as compressor blades and impellers are primary components in the cold section for any turbine engine. The compressed air from the compressor section then enters the combustor section, where a ring of fuel nozzles injects a steady stream of fuel. The injected fuel is ignited by a burner, which significantly increases the energy of the compressed air.
The high-energy compressed air from the combustor section then flows into and through the turbine section, causing rotationally mounted turbine blades to rotate and generate energy. Specifically, high-energy compressed air impinges on turbine vanes and turbine blades, causing the turbine to rotate. The air exiting the turbine section is exhausted from the engine via the exhaust section, and the energy remaining in this exhaust air aids the thrust generated by the air flowing through a bypass plenum.
Gas turbine engines, such as the one described above, typically operate more efficiently with increasingly hotter turbine temperatures. To maximize the efficiency of gas turbine engines, attempts have been made to form rotor components, such as compressor impellers and turbine discs having higher operating temperature capabilities. In particular, there is considerable commercial interest in superalloys for compressor and turbine rotating components which exhibit strength and creep resistance at relatively high temperatures (e.g., 1300-1500 F.°), as well as resistance to fatigue crack initiation at relatively lower temperatures (e.g., 500-1100 F.°). Many gas turbine engine components are now being made of nickel-based superalloys, which exhibit high temperature strength, but can be both difficult and costly to manufacture.
Many titanium (Ti) engine components, such as compressor impellers and disks, are currently being replaced by nickel (Ni) based components, including nickel based superalloys, with an addition of significant weight. In addition, the components, or methods of fabrication, do not include for any means for internal cooling of components within the component structure. Furthermore, special coatings may be required to mitigate environmental degradation of these titanium (Ti) and/or nickel (Ni) alloy components.
Temperatures within future gas turbine engines are increasing beyond the capabilities currently available from Ti and Ni based alloys. There is a need for gas turbine rotor components and a method of fabricating these rotor components that include a means for reducing the weight of the components and provides cooling of the components thereby enabling more efficient operation at higher temperatures. In addition it is desirable that the improved components and method of forming the components result in a cost effective method of manufacture and resultant component part. The present invention addresses one or more of these needs.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.